Efficient near-field communication based on audio signals

ABSTRACT

The present disclosure describes an efficient computer-implemented near-field communication system and method based on broadcasting audio signals for dynamically providing context-related additional content to a mobile device. In embodiments of the present invention, the additional content is mapped to specific audio watermarks and/or triggering commands which are encoded together into a digital signal. Based on continuously scanning the received background noise, an exactly defined frequency range and volume is dynamically selected for broadcasting the signal. Hence, the encoded digital signal is further modulated into an audio signal in the exactly defined frequency range. In embodiments of the present invention, the selected exactly defined frequency range for transmitting the audio signal may preferably be located in the ultrasound and/or infrasound frequency range. In case of transmitting infrasound signals, gyrosensors of the mobile device may be employed as audio signal receivers in embodiments of the present invention. Moreover, in further embodiments of the present invention, audio signal receiver of a mobile device such as gyrosensors or microphones may be switched on by transmitting a command via a wireless network such as Wifi or Bluetooth. Also the information about the selected frequency range and volume for broadcasting the audio signal may be provided to the mobile device via a wireless network in embodiments of the present invention. In response, an audio signal receiver of the mobile device may be tuned to the selected frequency range. The received audio signal is further processed on the mobile device so that the context-related additional content may be displayed and/or rendered.

TECHNICAL FIELD

The present disclosure relates to methods and systems for dynamicallyproviding context-related additional content to mobile devices bybroadcasting audio signals.

BACKGROUND

Near-field communication based on sending and receiving encoded acousticaudio signals in both the audible and the inaudible frequency range forproviding additional, customized content has been used in the art for awhile now. In said method, audio signals comprising an audio watermarkwhich unambiguously identifies a piece of content are broadcasted tomobile devices located in direct vicinity. The mobile devices receivesaid audio signals via their microphones and are further able toretrieve the additional information from a database located on a serverbased on identifying the audio watermark. It is pointed out thatthroughout this description, the term “audio signal” is used in itsspecific meaning of “acoustic audio signal”.

Especially vendors and service providers have taken advantage of thismethod of communication with customers being physically present and thusbeing able to provide them with up-to-date information and customizedoffers taking into account the customers' specific context. Moreover,audio signals captured by the microphone of a mobile device from theambient environment have also been used to enhance the accuracy ofindoor navigation, since satellite-based navigation systems such as GPSgenerally do not work well in indoor environments.

However, the process of demodulating the complex protocol of a receivedencoded and modulated audio signal on a mobile device consumes a largenumber of computing resources. Hence, it would be desirable to initiatesaid resource-intensive process of demodulating an audio signal merelyfor those received audio signals which actually contain audiowatermarks. Misdetections of audio signals which do not comprise anyaudio watermarks as they e.g. form part of the background noise presentin the respective environment around a mobile device should be avoidedin order to save the battery resources of a mobile device and thus toextend its overall lifetime. Likewise, in prior art systems, a lot ofbattery power is consumed by the numerous sensors such as e.g. the audiosignal receivers of a mobile device waiting to detect an audio signalcomprising an audio watermark. Further, also the process of generatingand broadcasting audio signals needs a lot of energy.

Moreover, most near-field communication systems based on audio signalsdescribed in the prior art are limited to a rather small local rangearound an audio signal transmitter. However, in some situations, itmight be preferable to be able to receive an audio signal by a mobiledevice which is located further away from an audio signal transmitterand/or located in areas shielded by obstacles such as walls.

Hence, it is the object of the present invention to provide systems andmethods enabling near-field communication based on audio signals in anefficient way.

This object is solved by the subject matter of the independent claims.Preferred embodiments are defined by the dependent claims.

SUMMARY

In the following, a summary is provided to introduce a selection ofrepresentative concepts in a simplified form that are further describedbelow in the detailed description. This summary is not intended toidentify key features or essential features of the claimed subjectmatter, nor is it intended to be used in any way that would limit thescope of the appended claims.

Briefly, the subject matter of the present invention is directed towardsa computer-implemented method for dynamically providing context-relatedadditional content to a mobile device by broadcasting audio signals by acomputing device. Hereby, the additional content is provided in adatabase or in databases on a server device which comprises look-uptables of audio watermarks mapped to specific context-related contentand look-up tables for triggering commands mapped to specificcontext-related events. A computing device configured to broadcast anaudio signal to mobile devices located in its vicinity accesses saiddatabase via a wireless network and extracts a specific watermark and/ortriggering command.

In a next step, said specific watermark and/or triggering command areencoded into a digital signal using error correcting encoding. In orderto further enhance security, in embodiments of the present invention, abit length corresponding to the data part of the signal and a bit lengthcorresponding to the key shared between the broadcasting computingdevice and the receiving mobile device are configured to changedynamically. Moreover, in further embodiments, also the mapping of eachspecific piece of content to a specific watermark and/or of eachspecific event to a triggering command is configured to changeautomatically on a regular basis.

Subsequently, in a first method of the present invention, an exactlydefined frequency range which is least hampered by background noisepresent in the environment surrounding a broadcasting computing deviceis selected by continuously scanning received audio signals.Additionally, also the volume of the audio signal to be broadcasted maybe selected to be so high that the audio signal is very well detectableat an audio signal receiver of a mobile device located in the vicinityof the broadcasting computing device.

Based on the selected frequency range and possibly volume, the encodeddigital signal is further modulated into an audio signal in the selectedexactly defined frequency range using modulation schemes such as forexample quadrature amplitude modulation (QAM). In embodiments of thepresent invention, the selected exactly defined frequency range fortransmitting the audio signal may preferably be located in theultrasound and/or infrasound frequency range. However, in embodiments ofthe invention, the audio signal may also be broadcasted in the audiblefrequency range.

Subsequently, in an embodiment of the present invention, it is furtherfeasible to switch on a previously switched off audio signal receiver ofthe mobile device such as a microphone by transmitting a command fromthe computing device to the mobile device via a wireless network.Hereby, in embodiments of the present invention, the wireless networkmay be a WIFI network or a Bluetooth network.

Moreover, also using the wireless network, a further command may betransmitted to the mobile device comprising information about theselected exactly defined frequency range and the volume of the audiosignal to be broadcasted. In further embodiments of the presentinvention, said information may also be transmitted by an acousticbroadband signal, when an audio signal receiver such as a microphone ofthe mobile device is already switched on.

Once said command to switch on an audio signal receiver of the mobiledevice and/or said information about the selected exactly definedfrequency range and volume are received by the mobile device, the audiosignal receiver of the mobile device is switched on and subsequentlytuned to the selected frequency range.

In embodiments of the present invention, an audio signal receiver of amobile device further or alternatively has to receive a triggeringsignal within a selected exactly defined frequency range before thesignal processing component eventually begins the veryresource-intensive process of demodulating the complex QAM or comparableprotocol of an encoded and modulated audio signal transmitting theadditional context-related content.

Then, in a next step of a first method of the present invention, anaudio signal is broadcasted by the audio signal transmitter of thecomputing device and received by the audio signal receiver of the mobiledevice. Said received audio signal is further demodulated and decoded inorder to derive the specific watermark and/or triggering command.

Moreover, in a first method of the present invention, the database onthe server device is searched in order to determine the specific contentand/or specific event related to the derived specific watermark and/ortriggering command. Finally, said specific content and/or specific eventis displayed and/or rendered on the mobile device.

In a second method of the present invention, context-related additionalcontent may be provided to a mobile device by broadcasting audio signalsmerely in the infrasound frequency range. As in the first methoddescribed above, also in this second method a database or databases on aserver device providing additional content, in which each specific pieceof content is mapped to a specific watermark and/or a specific event ismapped to a triggering command, is accessed via a wireless network and aspecific watermark and/or triggering command is extracted in a firststep.

Then, said specific watermark and/or triggering command are encoded intoa digital signal in the same way as described above with respect to thefirst method of the present invention. Said digital signal is furthermodulated into an audio signal in the infrasound frequency range usingmodulation schemes such as those mentioned above for the first method ofthe present invention.

In a next step of said second method of the present invention, a commandto switch on a gyrosensor of the mobile device is transmitted via awireless network. When said command is received by the mobile device,said gyrosensor of the mobile device is switched on so that it is ableto receive a broadcasted infrasound signal.

As described above with respect to the first method of the presentinvention, also in said second method of the present invention saidreceived infrasound audio signal subsequently is demodulated and decodedin order to derive the specific watermark and/or triggering command.Finally, in said second method of the present invention, the database issearched in order to determine the specific content and/or specificevent related to the derived specific watermark and/or triggeringcommand. Said specific content and/or specific event is then displayedand/or rendered on the mobile device.

In further embodiments, said first and said second method of the presentinvention may also be performed in the reverse direction. Hence,context-related additional content may also be provided from a mobiledevice to a computing device by broadcasting audio signals.

In embodiments of the present invention, the computing device and themobile device may also be equipped with at least one of globalnavigation satellite system receivers and optical sensors.

Moreover, in both the first and second method of the present invention,a triggering command may be extracted on the mobile device from thereceived audio signal which triggers retrieving all relevantcontext-related additional content from the database. Then, all saidretrieved relevant context-related additional content may be cached onthe mobile device. Hence, in said embodiment, it is further sufficientto track the location of the mobile device to be able to display and/orrender the appropriate context-related additional content on the mobiledevice.

In further embodiments of the present invention, a same watermark may beencoded together with different triggering commands triggering differentspecific events occurring while a similar context-related content isdisplayed or rendered on a mobile device. Similarly, a same triggeringcommand may be encoded together with different watermarks leading to asimilar or same event to be triggered together with completely differentcontext-related content being displayed or rendered on a mobile device.

In all of the described different embodiments of the present invention,additionally user-specific parameters such as user profiles may be takeninto account when providing context-related content.

In further aspects, a computer-readable medium is provided that hasthereon stored computer-readable instructions that, when run on acomputer, are configured for performing the steps of any of the methodsdescribed above.

In addition, a computer-implemented system is provided in the presentinvention for dynamically providing context-related additional contentfrom a computing device to a mobile device by broadcasting audio signalsby the computing device. Said system comprises a database or databaseson a server device providing the context-related additional content, inwhich each specific piece of content is mapped to a specific watermarkand/or a specific event is mapped to a triggering command. In aspects ofthe present invention, the computing device comprises at least asoftware component accessing the database via a wireless network andextracting a specific watermark and/or triggering command, a signalprocessing component performing the steps of encoding said specificwatermark and/or triggering command into a digital signal, selecting anexactly defined frequency range and a volume based on continuouslyscanning noise signals present in the surrounding environment and usingmodulation schemes to modulate said digital signal into an audio signalin the selected exactly defined frequency range and an audio signaltransmitter configured to broadcast said audio signal. In furtheraspects of the present invention, the system contains a wireless networkconnecting the computing device, the mobile device and the server devicewhich is configured for accessing the database and for transmitting acommand to switch on an audio signal receiver of the mobile device andfor transmitting information about the selected frequency range andvolume from the computing device to the mobile device. Moreover, inaspects of the present invention, the mobile device of thecomputer-implemented system comprises at least an audio signal receiverconfigured to receive said audio signal broadcasted by the audio signaltransmitter of the computing device, a signal processing componentconfigured to perform the steps of tuning the audio signal receiver tothe selected frequency range and demodulating and decoding said receivedaudio signal in order to derive the specific watermark and/or triggeringcommand. Further, an application on the mobile device is configured toperform the steps of searching the database in order to determine thespecific content and/or specific event related to the derived specificwatermark and/or triggering command and displaying and/or rendering saidspecific content and/or specific event on a display of the mobiledevice.

In a further embodiment of the present invention, anothercomputer-implemented system for dynamically providing context-relatedadditional content from a computing device to a mobile device bybroadcasting audio signals in the infrasound frequency range isprovided. Said computer-implemented system of said further embodiment ofthe present invention comprises a database or databases on a serverdevice providing the context-related additional content, in which eachspecific piece of content is mapped to a specific watermark and/or aspecific event is mapped to a triggering command. The computing deviceof said another computer-implemented system of the present inventioncomprises at least a software component accessing the database via awireless network and extracting a specific watermark and/or triggeringcommand, a signal processing component performing the steps of encodingsaid specific watermark and/or triggering command together into adigital signal, and using modulation schemes to modulate said digitalsignal into an audio signal in the infrasound frequency range and anaudio signal transmitter configured to broadcast said audio signal inthe infrasound frequency range. Moreover, said anothercomputer-implemented system of the present invention comprises awireless network connecting the computing device, the mobile device andthe server device and which is configured for accessing the database andfor transmitting a command to switch on a gyrosensor of the mobiledevice. Finally, the mobile device of the another computer-implementedsystem of the present invention comprises at least a gyrosensorconfigured to receive said infrasound audio signal broadcasted by theaudio signal transmitter of the computing device, a signal processingcomponent configured to perform the steps of demodulating and decodingsaid received audio signal in order to derive the specific watermarkand/or triggering command and an application configured to search thedatabase in order to determine the specific content and/or specificevent related to the derived specific watermark and/or triggeringcommand and to display and/or render said specific content and/orspecific event on a display of the mobile device.

Other advantages may become apparent from the following detaileddescription when taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram that shows the components of a system fordynamically providing context-related additional content to a mobiledevice by broadcasting audio signals by a computing device according toembodiments of the present invention.

FIG. 2 is a flow diagram that illustrates a method for dynamicallyproviding context-related additional content to a mobile device bybroadcasting audio signals by a computing device, according to oneembodiment of the present invention.

FIG. 3 is a flow diagram that shows a method for dynamically providingcontext-related additional content to a mobile device by broadcastingaudio signals by a computing device in the infrasound frequency range,according to another embodiment of the present invention.

FIG. 4 depicts an example environment for employing a system and methodfor dynamically providing context-related additional content to a mobiledevice by broadcasting audio signals by a computing device according toembodiments of the present invention.

FIG. 5 shows another example environment for employing a system andmethod for dynamically providing context-related additional content to amobile device by broadcasting audio signals by a computing deviceaccording to embodiments of the present invention.

FIG. 6 shows an example environment for employing a system and methodfor dynamically extracting context-related additional content from amobile device by broadcasting audio signals by the mobile deviceaccording to embodiments of the present invention.

DETAILED DESCRIPTION

FIG. 1 shows an example implementation 100 of an unique audio identifiersynchronization system for providing context-related additional content.Said unique audio identifier synchronization system comprises at least aSonoBeacon device 102 according to the present invention, which is ageneral computing device including components for data storing 104 anddata processing 106, and a mobile device 108 such as a smartphone, atablet, a PDA, a handheld computer, a smartwatch etc. However, thesedevices rather serve as illustrative examples of mobile devices and alsoadditional and/or further devices may be used in the unique audioidentifier synchronization system of the present invention. TheSonoBeacon device 102 and the mobile device 108 are connected by anetwork 110 such as for example the Internet, LAN, WIFI, Bluetooth etc.Therefore, both the SonoBeacon device 102 and the mobile device 108 maybe Bluetooth enabled devices and thus both comprise Bluetooth sensors112, 114 and the SonoBeacon device 102 may also include a WIFI router116 providing a WIFI to which a mobile device 108 may connect via a WIFIreceiver 118.

At the same time, communication between the SonoBeacon device 102 andthe mobile device 108 can be performed by sound signals 120 in any ofthe audible range, the ultrasound range and/or the infrasound range. Inorder to be able to communicate between each other by sound signals 120,both the SonoBeacon device 102 and the mobile device 108 are equippedwith signal processing components 122, 124 whose details will be furtherdiscussed later with respect to FIGS. 2 and 3. Said signal processingcomponents 122, 124 are configured to generate an encoded, modulatedaudio signal from one or more digital signatures and signals and arealso configured to extract a digital signal and/or signature from anencoded, modulated audio signal.

Moreover, both the SonoBeacon device 102 and the mobile device 108include audio signal transmitters 126, 128 such as, e.g., loudspeakers,and audio signal receivers 130, 132 such as, e.g., microphones.Additionally, for receiving sound signals in the infrasound range, alsogyrosensors 134 of the mobile device 108 may be utilized. Hereby, theaudio signal transmitters 126, 128 and audio signal receivers 130, 132may be separate devices or may be combined to form a single device. Inanother embodiment, the audio signal transmitters 126, 128 and/or theaudio signal receivers 130, 132 may also be combined with the signalprocessing components 122, 124 into a single device.

Both the SonoBeacon device 102 and the mobile device 108 may act asglobal navigation satellite system receivers and hence compriseequipment 136, 138 for receiving signals from satellite systems such asGPS, Galileo, GLONASS, Beidou etc. Further, both the SonoBeacon device102 and the mobile device 108 may include additional sensors such as forexample optical sensors 140, 142.

The mobile device 108 further comprises a memory 144 for storing data aswell as a display 146 for displaying all kinds of graphic and multimediacontent. A prerequisite for the functioning of the audio identifiersynchronization system of the present invention for providingadditional, customized, context-related content to a mobile device 108is an installed SonoBeacon Application 148 on the mobile device 108 anda corresponding SonoBeacon software component 150 on the SonoBeacondevice 102.

The additional, customized, context-related content to be provided to auser of a mobile device 108 is originally stored on a server device 152.Said server device 152 may be a separate entity which may be accessedfrom the SonoBeacon device 102 and from the mobile device 108 throughthe network 110. Alternatively, the server device 152 may be also partof the SonoBeacon device 102 and/or of the SonoBeacon Application 148 onthe mobile device 108. The server device 152 may comprise a database 154of look-up tables of audio watermarks 156 mapped to specificcontext-related content 158 and a database 160 of look-up tables fortriggering commands 162 mapped to specific context-related events 164 tooccur. Such events 164 may disclose for example an acoustic signal, anoptical signal, a pop-up notice, etc. Said databases 154, 160 of audiowatermarks 156 and of triggering commands 162 may be separate databases,split up into several databases or may alternatively be combined to formone single lookup database including a mapping of audio watermarks 156to specific context-related content 158 and of triggering commands 162to specific context-related events 164. It is important that saidlook-up tables of audio watermarks 156 and of triggering commands 162may be accessed by both the SonoBeacon device 102 and by the mobiledevice 108, respectively. The server device 152 may additionallycomprise a database 166 storing a plurality of user profiles 168 ofusers of the SonoBeacon Application 148. Alternatively, the user profile168 of an individual SonoBeacon Application 148 user may also be storedlocally on a user's mobile device 108.

Referring to FIG. 2, a method for dynamically providing context-relatedadditional content 158 to a mobile device 108 by broadcasting audiosignals 120 using a computing device 102 such as the SonoBeacon device102 is discussed. The method may also be performed in the oppositedirection, i.e. the mobile device 108 may also provide context-relatedadditional content 158 to a computing device 102 such as, e.g., theSonoBeacon device 102 by broadcasting audio signals 120.

First of all, the case of an audio signal 120 being generated at acomputing device 102 such as for example the SonoBeacon device 102 isillustrated. In a first step, the SonoBeacon software component 150 ofthe SonoBeacon device 102 accesses 204 the databases 154, 160 of audiowatermarks 156 and/or triggering commands 162, which can be eitherstored locally on the SonoBeacon device 102 or may be stored on aseparate server 152. In the case that said databases 154, 160 aremaintained on a separate server device 152, the SonoBeacon device 102accesses them over a network 110 such as the internet or Bluetooth. Thecontent of said databases 154, 160 may have been provided 202 by anadvertiser such as the owner of the SonoBeacon device 102 and/or anexternal advertiser in either a pre-broadcasting phase or may be createdon the fly by a user of a mobile device 108 equipped with the SonoBeaconApplication 148. Each specific piece of content 158 is thereby mapped toa specific watermark 156 and each specific event 164 is mapped to aspecific triggering command 162. For security reasons, this mapping ofwatermarks 156 and triggering commands 162 to specific pieces of content158 and specific events 164, respectively, may be implemented to changeautomatically on a regular basis. When the SonoBeacon software component150 accesses 204 the databases 154, 160, it extracts 204 a specificwatermark 156 and/or triggering command 162 which it wants to broadcastto mobile devices 108 located in its environment.

Said extracted specific watermark 156 or triggering command 162 areencoded 206 into a digital signal using an error correcting coding. Ifboth a specific watermark 156 and a triggering command 162 are extractedfrom a database, they are both encoded together into a digital signalusing error correcting coding. Hereby, the transmitted data rate iscalculated in a variable way, which means that the actual bit lengthcorresponding to the data part of the signal changes dynamically. Theinformation about the number of data bits comprised in the broadcastedsignal is contained in the first, so called start bits of thebroadcasted signal. Hence, it is rendered more difficult for a wiretapper to identify the correct number and types of bits belonging to thebroadcasted data. Moreover, also the number of bits of the key which isshared between the SonoBeacon device 102 and a mobile device 108 is keptvariable. Further, also the seed for generating a shared key is permutedregularly in order to further enhance security of data transmission.

The resulting digital signal is configured to trigger mobile devices 108in a context sensitive way, this context being provided based on thewatermark 156 being part of the encoded signal. Using encoding 206 inthe form of error correction encoding however, may serve only as anillustrative example for encoding a specific watermark 156 and atriggering command 162 together into one resulting digital or analogsignal. In other implementations, further, alternative or additionalencoding techniques may be used to generate a digital signal based onencoding the acoustic watermark 156 and the triggering command 162.

At the same time, the signal processing component 122 of the SonoBeacondevice 102 which is configured to broadcast a specific, context-relatedcontent continuously scans 208 the noise signals received by its audiosignal receiver 130 such as a microphone. These received noise signalsare processed by the signal processing component 122 in order toidentify an exactly defined frequency range which is least hampered byacoustic noise from the environment.

Moreover, the signal processing component 122 determines which volumemay be necessary for broadcasting audio signals 120 based on theanalysis of the received acoustic noise so that the resulting audiosignal will still be clearly noticeable at the audio signal receiver 132of a mobile device 108 located at a maximum distance from thebroadcasting audio signal transmitter 126 of the SonoBeacon device 102,for which correct functionality of the near-field communicationtechnique disclosed in the present application is still guaranteed. Insome example implementations, this maximum distance from the SonoBeacondevice 102 may be selected to be very small in order to ensure that theaudio signal 120 may only be detectable and decipherable if respectivemobile devices 108 are located very close to the audio signaltransmitter 126 of the SonoBeacon device 102. In other, alternative oradditional implementations, frequency range and volume may be tuned suchthat the audio signal 120 is detectable and decipherable in a preferablylarge range up to the maximum distance possible based on the techniquedisclosed herewith in order to address also far away mobile devices 108.In further implementations, the audio signal 120 may always bebroadcasted by the audio signal transmitter 126 of the SonoBeacon deviceat the highest volume possible.

Subsequently, an exactly defined frequency range and possibly a volumeare selected for broadcasting the audio signals 120. This process offinding an appropriate frequency range for transmitting an audio signal120 is further particularly important in embodiments in which theSonoBeacon device 102 transmits audio signals 120 comprising differentwatermarks 156 and/or trigger commands 162 instantaneously to a numberof different mobile devices 108.

In aspects of the present invention, an exactly defined frequency rangeis selected 210 that is non-audible for an average human ear, since itis either in the ultra- or in the infrasound frequency range.Alternatively however, also a frequency range may be selected 210 thatis indeed audible for humans.

The encoded digital signal is then modulated 212 into a high or lowfrequency audio signal 120 depending on the selected exactly definedfrequency range and the selected volume using modulation schemes, forexample amplitude shift keying (ASK), amplitude modulation, frequencyshift keying (FSK), frequency modulation and/or quadrature amplitudemodulation (QAM). QAM conveys message signals by modulating theamplitudes of two carrier waves using ASK and/or FSK. These two carrierwaves of the same frequency are out of phase by 90°. The modulated wavesare then summed and the resulting signal is a combination of phase-shiftkeying (PSK) and amplitude-shift keying (ASK). These modulation schemes,however, only serve as examples of modulation schemes. Moreparticularly, alternative and/or additional modulation schemes, forexample further digital modulation schemes, may be used for generatingthe high or low frequency audio signal 120 from the encoded signal. Insome example implementations, in particular a combination of several ofthese modulation schemes may apply, for example a combination offrequency FSK and amplitude shift keying ASK.

As can be seen from FIG. 1, both the SonoBeacon device 102 and themobile device 108 are equipped—apart from with audio signal receivers130, 132—also with sensors enabling wireless connections via Bluetooth112, 114 and Wifi 116, 118. In an embodiment of the present invention,the SonoBeacon device 102 may act as a WIfI-router 116 to which a mobiledevice 108 in its vicinity may connect. For example, the mobile device108 may be able to detect WIfI networks 110 while its audio signalreceiver 132 is still switched off. Therefore, in the vicinity of aSonoBeacon device 102, the mobile device 108 may be able to detect aWIfI network 110 provided by the WIfI-router 116 located on theSonoBeacon device 102. This SonoBeacon WIfI 110 may be furtherconfigured such that mobile devices 108 on which the SonoBeaconApplication 148 is installed require no password for connecting to it.As soon as a signal originating from a SonoBeacon WIfI router 116 isdetected on a mobile device 108 on which the SonoBeacon Application 148is installed, the SonoBeacon Application 148 may automatically connectthe mobile device 108 to the SonoBeacon WIfI 110. The SonoBeacon device102 may, on the other hand, be configured such that it automaticallytransmits 214 a command to newly connected mobile devices 108instructing a user by e.g. displaying a pop-up message to switch on 216an audio signal receiver 132 such as, e.g., a microphone. In analternative embodiment, a user of the mobile device 108 may also selectin the settings of the SonoBeacon Application 148 that an audio signalreceiver 132 is automatically switched on 216 when the mobile device isconnected to a SonoBeacon WIFI 110. Hence, transmitting 214 a command toswitch on 218 an audio signal receiver 132 of a mobile device 108 via aWIFI network 110 obviates the need to keep an audio signal receiver 132of a mobile device 108 such as a microphone always switched on. Byswitching on an audio signal receiver 132 only in the presence of aSonoBeacon device 102 while keeping it switched off most of the timegreatly reduces battery consumption of a mobile device 108. Moreover,the established WIFI connection 110 between the SonoBeacon device 102and the mobile device 108 via the SonoBeacon WIFI 110 may be used totransmit 218 the information about the selected exactly definedfrequency range and possibly volume for broadcasting the audio signal120 from the SonoBeacon device 102 to the mobile device 108.

Equivalently, in an alternative embodiment, the Bluetooth sensors 114 ofa mobile device 108 of a user entering an area within the range of aSonoBeacon device 102 may be switched on, while the audio signalreceiver 132 may be still switched off. Due to the switched on Bluetoothsensor 114 of the mobile device 108, the SonoBeacon device 102 isenabled to detect the presence of the mobile device 108 via Bluetooth.Hence, a user of the mobile device 108 may receive a notification byBluetooth telling him or her to switch on 216 the audio signal receiver132 of his or her mobile device 108 in order to be able to receive audiosignals 120 from a SonoBeacon device 102. Moreover, in a same way asdescribed above in the case of a WIFI connection 110 between theSonoBeacon device 102 and the mobile device 108, also the set upBluetooth connection 110 between the two devices may be utilized totransmit 218 the information about the selected exactly definedfrequency range and possibly volume for broadcasting the audio signal120 from the SonoBeacon device 102 to the mobile device 108.

Based on this information about the selected exactly defined frequencyrange, the signal processing component 124 of the mobile device 108 maybe able to tune 220 the audio signal receiver 132 such as e.g. amicrophone of the mobile device 108 to exactly the selected frequencyrange, in which the actual audio signal 120 transmitting additionalcontent 158 will be expected. Moreover, the SonoBeacon Application 148may instruct the signal processing component 124 to perform the costlysteps of demodulating and decoding received audio signals 120 only foraudio signals 120 received within the clearly defined frequency rangeand alternatively additionally at a certain volume. Any received audiosignals 120 which do not comply with the information transmitted fromthe SonoBeacon device 102 to the mobile device over a wireless network110 such as e.g. WIFI or Bluetooth will not be considered by the signalprocessing component 124 of the mobile device 108. Since thedemodulation of the complex QAM or comparable protocol and the decodingalgorithm is not erroneously performed for noise signals and since theaudio signal receiver 132 does not need to search the whole frequencyrange for detecting the actual signal 120, computing resources may besaved and finally energy consumption may be significantly reduced on themobile device 108, extending lifetime of its battery.

In alternative embodiments of the present invention, the informationabout the selected exactly defined frequency range and possibly also thevolume for broadcasting an audio signal 120 providing context-relatedadditional content 158 to a mobile device 108 may also be transmitted218 to the mobile device 108 by an acoustic broadband signal. The signalprocessing component 122 of the SonoBeacon device 102 may generate sucha broadband signal, which is then broadcasted by the audio signaltransmitter 126 of the SonoBeacon device 102. The audio signal receiver132 of a mobile device 108 located in the proximity of the SonoBeacondevice 102 receives this acoustic broadband signal. This acousticbroadband signal can be easily detected without querying the wholefrequency range due to its broadband character. The signal processingcomponent 124 of the mobile device 108 processes this broadband signaland thus the information about the frequency range in which the actualaudio signal 120 will be transmitted and the expected volume of theactual audio signal 120 can be obtained by the SonoBeacon Application148 of the mobile device 108 so that the audio signal receiver 132 maybe tuned 220 to the selected exactly defined frequency range.

In embodiments of the present invention, the audio signal receiver 132of the mobile device 108 further has to receive a triggering signalwithin the selected exactly defined frequency range before the signalprocessing component 122 eventually begins the very resource-intensiveprocess of demodulating the complex QAM or comparable protocol of anencoded and modulated audio signal 120 transmitting the additionalcontext-related content. Whereas an encoded and modulated audio signal120 generally comprises 24 bit, whereby also any other bit length ispossible and comprised in embodiments of the present invention, thetriggering signal usually merely comprises a few bits. Therefore, it canbe processed in a very light and resource-efficient way. Hence, saidtriggering signal triggers the SonoBeacon Application 148 to “listen” toany subsequently broadcasted audio signal and to process it accordinglyin the way described in the following.

In alternative embodiments of the present invention, the SonoBeaconApplication 148 on a mobile device 108 may also be pre-programmed toreceive the encoded and modulated audio signal 120 in a fixed frequencyrange. Hence, it may not be necessary to transmit information about anexactly defined frequency range from a SonoBeacon device 102 to a mobiledevice 108. Instead, the audio signal receiver 132 of the mobile device102 is automatically tuned to the fixed frequency range in which itreceives a light, easy-to-decipher triggering signal informing theSonoBeacon Application 148 to process any encoded and modulated audiosignals 120 which will be received from now on.

In a next step, the encoded and modulated audio signal 120 is thenbroadcasted 222 via the audio signal transmitter 126 of the SonoBeacondevice 102, i.e. the modulated high or low frequency audio signal 120 isplayed back by the audio signal transmitter 126, e.g. a loudspeaker, tobe broadcasted 222 into its surrounding environment. In exampleimplementations, this surrounding environment of loudspeaker 126 mayencompass a range of 5 to 7 meters, in some example implementations thisrange may be up to 10 meters.

The encoded and modulated audio signal 120 may in some exampleimplementations be broadcasted 222 as a single audio signal, i,e,standalone. In some example implementations, the encoded and modulatedaudio signal 120 may also be overlaid on some basic acoustic signal,e.g. audio broadcast or background music being played in a mall orsupermarket via public speakers, or the like.

Within this surrounding environment, the audio signal receiver 132 of amobile device 108 may be able to receive 224 the encoded and modulatedaudio signal 120 broadcasted 222 by the audio signal transmitter 126 ofthe SonoBeacon device 102. The audio signal receiver 132 of the mobiledevice 108 may be a microphone or be coordinated as an array ofmicrophones.

Subsequently, the signal processing component 124 of the mobile device108 can demodulate 226 the recorded audio signal 120 to reproduce theencoded, unmodulated signal. Hereby, the signal processing component 124is similar to the signal processing component 122 of the SonoBeacondevice 102 and hence capable of performing the same method steps in areverse direction. The signal processing component 124 may form aseparate component or may be included into the SonoBeacon Application148 previously installed on the mobile device 108.

After having demodulated 226 the audio signal 120 to receive the digitalsignal, the signal processing component 124 decodes 228 the digitalsignal using decoding schemes that match the initially applied codingschemes, e.g. the error correcting coding that was initially applied tocreate the digital signal by the signal processing component 122 of theSonoBeacon device 102. After this, e.g. error correcting decoding 228 ofthe demodulated signal, the signal processing component 124 derives theoriginally unique audio watermark 156 and/or the triggering command 162.

The SonoBeacon Application 148 subsequently conveys the unique audiowatermark 156 and/or the triggering command 162 via a network 110 suchas wireless or wireline internet connections to the server 152comprising databases 154, 160 of look-up tables of audio watermarks 156mapped to specific context-related content 158 and triggering commands162 mapped to specific context-related events 164 to occur. Then, thedatabases 154, 160 are searched 230 in order to identify a match of areceived watermark 156 and/or received triggering command 162 withwatermarks 156 and triggering commands 162 previously stored in thedatabases 154, 160. The specific complementary content 158 related tothe identified acoustic watermark 156 is determined and particularevents 164 are looked up which are to occur according to the identifiedtriggering command 162. Such triggering commands 162 trigger theSonoBeacon Application 148 to execute an operation, for example emittinga specific sound, emitting a specific light signal and/or replaying anaudio or video file stored on the database or the mobile device 108.These operations, however, only serve as illustrative examples, and thusthe triggering command 162 may trigger a variety of different and/oradditional operations. Moreover, the triggering command 162 may alsotrigger a combination of different operations to be executed.

The SonoBeacon Application 148 is further triggered to pull therespective complementary content items 158 and/or events 164 from thedatabases 154, 160 and subsequently displays or renders 232 saidcomplementary content 158 and/or events 164 on the display 146 of themobile device 108.

It is important to note that in further embodiments of the presentinvention, the described process of transmitting audio signals may alsobe performed in the opposite direction, i.e. from the mobile device 108to the SonoBeacon device 102. The SonoBeacon Application 148 may extracta watermark 156 and/or triggering command 162 from the databases 154,160 of watermarks 156 and of triggering commands 162, respectively, orgenerate a new watermark 156 or triggering command 162, which is thenstored together with its specific content 158 or specific event 164 inthe lookup tables of the databases 154, 160. In a next step, theSonoBeacon Application 148 may trigger the signal processing component124 of the mobile device 108 to process the extracted or generatedwatermark 156 or triggering command 162 in the same way as the watermark156 and/or triggering command 162 is processed by the signal processingcomponent 122 of the SonoBeacon device 102. Hence, at first errorcorrecting encoding is performed on the watermark 156 and/or triggeringcommand 162, before modulation schemes are applied to generate anencoded, modulated audio signal 120 in a frequency range which is nothampered by background acoustic noise. The SonoBeacon device 102 may beinformed about the selected frequency range and volume for broadcastingthe encoded and modulated audio signal 120 by a signal transmitted overa wireless network 110 such as a WIFI or Bluetooth or alternatively by abroadband acoustic signal. The encoded, modulated audio signal 120 isthen broadcasted by the audio transmitter device 128 of the mobiledevice 108 such as, e.g., a loudspeaker, into the near environment ofthe mobile device 108. If the mobile device 108 is located in proximityto a SonoBeacon device 102, this SonoBeacon device 102 may receive saidtransmitted audio signal 120 with its audio signal receiver 130. Hereby,the audio signal receiver 130 of the SonoBeacon device 102 may be forexample a microphone. Subsequently, the processes of demodulation anddecoding, which have been described above to be performed on the mobiledevice 108, are performed by the signal processing component 122 of theSonoBeacon device 102. Finally, the SonoBeacon software component 150accesses the databases 152, 160 of watermarks 156 and triggeringcommands 162 in order to identify the specific content 158 related tothe received watermark 156 and/or triggering command 162.

Referring to FIG. 3, a method for dynamically providing context-relatedadditional content 158 to a mobile device 108 by broadcasting audiosignals 120 using a computing device 102 such as the SonoBeacon device102 specifically in the infrasound frequency range is discussed.

As discussed already in the embodiment of FIG. 2, first of all,additional content 158 is provided 302 to a database 154 by anadvertiser such as the owner of the SonoBeacon device 102 and/or anexternal advertiser in either a pre-broadcasting phase or may be createdon the fly by a user of a mobile device 108 equipped with the SonoBeaconApplication 148. Each specific piece of content 158 is thereby mapped toa specific watermark 156 or and each specific event 164 is mapped to atriggering command 162. For security reasons, this mapping of watermarks156 and triggering commands 162 to specific pieces of content 158 andspecific events 164, respectively, may be implemented to changeautomatically on a regular basis. When the SonoBeacon software component150 accesses 304 the databases 154, it extracts 304 a specific watermark156 and/or triggering command 162 which it wants to broadcast to mobiledevices 108 located in its environment. Said databases 154, 160 may beeither maintained locally on the SonoBeacon device 102 or may be storedon a separate server 152. If the databases 154, 162 are maintained on aseparate server, it is accessed 304 by the SonoBeacon software component150 over a network 110 such as the internet or Bluetooth.

Said extracted specific watermark 156 and/or triggering command 162 areencoded 306 into a digital signal using an error correcting coding whichmay be further characterized by the same features for enhancing securitysuch as a variable bit lengths and permuted keys as described above withrespect to FIG. 2. Obviously and as mentioned above with respect to FIG.2, using encoding in the form of error correction encoding may serveonly as an illustrative example for encoding a specific watermark 156and a triggering command 162 together into one resulting digital oranalog signal and alternative or additional coding techniques may alsobe applied.

The encoded digital signal is then modulated 308 into a low frequencyaudio signal in the infrasound frequency range using modulation schemes,for example ASK, amplitude modulation, FSK, frequency modulation and/orQAM, which have been described in more detail above with respect to FIG.2.

In an embodiment of the present invention, the mobile device 108 isequipped with one or more gyrosensors 134, which generally serve todetermine the orientation of the display 146 of a mobile device 108based on measured accelerations. However, in an embodiment of thepresent invention, said one or more gyrosensors 134 of the mobile device108 may act as audio signal receivers 132 in the infrasound frequencyrange, since they may be excited by low frequency sound waves.

Like other audio signal receivers 132 described with respect to FIG. 2,also said one or more gyrosensors 134 are generally switched off on themobile device 108 when a user of the mobile device 108 enters an area inwhich audio signals 120 of a SonoBeacon device 102 are receivable.Sensors such as e.g. the one or more gyrosensors 134 of the presentembodiment of the invention generally consume a significant amount ofbattery power when kept in an active mode. However, as both theSonoBeacon device 102 and the mobile device 108 are further equippedwith sensors enabling wireless connections via Bluetooth 112, 114 andWIFI 116, 118, said one or more gyrosensors 134 of the mobile device 108may be switched on 312 by transmitting 310 a respective command to themobile device 108 via a wireless network 110. Such a wireless network110 between the SonoBeacon device 102 and the mobile device 108 may beestablished in a similar way as described above with respect to FIG. 2for example by the SonoBeacon device 102 acting as a WIFI-router 116providing a wireless network 110 to which the mobile device 108 mayconnect automatically by means of the SonoBeacon Application 148 or bysetting up a Bluetooth connection 110 between the SonoBeacon device 102and the mobile device 108.

In a next step, the encoded and modulated audio signal 120 is thenbroadcasted 314 via the audio signal transmitter 126 of the SonoBeacondevice 102, i.e. the modulated infrasound frequency audio signal isplayed back by the audio signal transmitter 126, e.g. a loudspeaker, tobe broadcasted 314 into its surrounding environment.

Audio signals 120 broadcasted 314 in the infrasound frequency range aregenerally detectable in a wider area around the audio signal transmitter126 compared to signals transmitted at larger frequencies in the audibleor ultrasound frequency range. Infrasound signals are able to penetratethrough materials such as walls. Therefore, particularly in indoorenvironments, broadcasting 314 audio signals 120 in the infrasoundwavelength range may significantly enhance the area in which an audiosignal 120 may still be detected.

The broadcasted encoded and modulated audio signal 120 in the infrasoundfrequency range is subsequently received 316 by the one or moregyrosensors 134 of the mobile device 108 located in the vicinity of theSonoBeacon device 102.

Subsequently and in the same way as described above with respect to FIG.2, the signal processing component 124 of the mobile device 108 candemodulate and then decode 318 the recorded infrasound audio signal inorder to derive the original, specific audio watermark 156 and/or thetriggering command 162.

In a next step and again similarly as in the embodiment described abovewith respect to FIG. 2, the SonoBeacon Application 148 searches 320 thedatabases 154, 160 in order to determine the specific content 158 and/orspecific event 164 related to the derived specific watermark 156 and/ortriggering command 162.

The SonoBeacon Application 148 further extracts the respectivecomplementary content items 158 and/or events 164 from the databases154, 160 and subsequently displays or renders 322 said specificcomplementary content 158 and/or specific events 164 on the display 146of the mobile device 108.

It should be pointed out that as illustrated in FIG. 1, both theSonoBeacon device 102 and the mobile device 108 described in embodimentsof the present invention may further comprise—in addition to audiosensors such as microphones 130, 132 and gyrosensors 134 and wirelessnetwork sensors such as Bluetooth 112, 114 and WIFI sensors 116,118—equipment 136, 138 for receiving signals from satellite systems suchas GPS, Galileo, GLONASS, Beidou etc. Hence, their exact location mayalso be determined by one of these global navigation satellite systems.In further embodiments, also optical sensors 140, 142 on both theSonoBeacon device 102 and the mobile device 108 may be employed in orderto set up a communication link.

These many different types of sensors comprised in the SonoBeacon device102 and in the mobile device 108 may be also configured to interact indifferent ways as merely in those described above with respect to FIGS.2 and 3. For example, in another embodiment of the present invention,the audio signal receiver 132 of a mobile device 108 in the vicinity ofa SonoBeacon device 102 may be turned on, but the WIFI receiver 118 maybe switched off. Since it might be advantageous to connect a mobiledevice 108 to a WIFI 110, for example in order to obtain thecontext-related specific contents 158 from a database or from databases154, 160 which are stored on an external server 152 or on the SonoBeacondevice 102 via a stable and fast internet connection, an audio signal120 may be transmitted by the audio signal transmitter 126 of theSonoBeacon device 102 to the audio signal receiver 132 of the mobiledevice 108 instructing a user to turn on the WIFI receiver 118 of themobile device 108. While being advantageous, a WIFI connection 110between a SonoBeacon device 102 and a mobile device 108 is not aprerequisite for the functioning of the general technique of providingadditional context-related content to a user of a mobile device 108 bysound signals 120. For example, some of the transmitted audio watermarks156 or triggering commands 162 may be directly executed by theSonoBeacon Application 148 without consulting a database 154, 160 with alookup table. Certain, limited contents may also be locally stored inthe SonoBeacon Application 148 of a mobile device 108. Based on theselocally stored contents and information, certain applications such as,e.g., navigation of a user of a mobile device 108, may become possiblewithout a connection to a network 110 such as the internet.

This point is further illustrated and explained with respect to FIG. 4,which depicts an example embodiment of the present invention. FIG. 4shows a building 400 such as for example a museum or a shopping mall, inwhich a user 402 equipped with a mobile device 404 on which theSonoBeacon Application is installed, may enter through entrances 406 or408. At both entrances 406 and 408, a SonoBeacon device 410 is located.For example purposes only, it is now assumed that all relevant sensorsof the user's 402 mobile device 404 are switched on and that hence it isnot necessary to switch on either sensors with the help of otheravailable sensors. However, all situations in which such a process ofswitching on different sensors is necessary once the user enters theenvironment of a SonoBeacon device are obviously included in the presentinvention.

As soon as a user 402 with a mobile device 404 on which the SonoBeaconApplication is installed enters the, e.g., museum 400 through one ofentrances 406 or 408, the audio signal receiver 412 of his or her mobiledevice 404 receives an encoded, modulated audio signal 414 from theSonoBeacon device 410 located at the entrance 406 or 408. Afterprocessing the received audio signal 414 as described above with respectto FIG. 2 or 3, a triggering command is extracted which triggers theSonoBeacon Application to retrieve all relevant content from a databaseand to cache it temporarily on the mobile device 404. For example, inthe case of a museum 400, all available explanations about the exhibitsin the museum 400 may be retrieved from an external server, which may bea part of the SonoBeacon device 410. In order to assure that thisretrieving of content from a server can be performed in a fast andefficient way, the mobile device 404 of the user 402 has beenautomatically connected to the SonoBeacon WIFI 416 provided by theSonoBeacon device 410, as detailed above.

To continue the example, the explanations about the exhibits of themuseum may be available in different languages such as English, German,French and Chinese. The SonoBeacon Application on a user's 402 mobiledevice 404 may automatically recognize the preferred language of a user402 due to the general language settings of the user's 402 mobile device404. Hence, the SonoBeacon Application which has been instructed by thereceived triggering command to retrieve all available explanations aboutthe exhibits of the museum 400 from a server does not have to retrievethese explanations in all available languages. Instead, if theSonoBeacon Application for example determines that the preferredlanguage of a user 402 is French, it merely obtains the explanations inFrench from the server to cache them on the mobile device 404.

Said example shows how the SonoBeacon technology may additionally takeinto account user specific parameters when providing context-relatedcontent. Further and even much more detailed user information may beused in the present invention. For example, the SonoBeacon Applicationmay be configured to be allowed to access a user's social media ore-mail account. Based on these and other activities and informationabout e.g. demographics or personal preferences provided directly by auser, a detailed personalized and dynamic user profile 168 may becreated and stored on the mobile device. These user profiles 168containing also data like characteristics of a user's history ofactivity while interacting with the SonoBeacon Application 148, featuresof a user's current and/or past geo-context as determined usingsatellite navigation systems such as GPS etc., date and time of day andthe like may be kept on the mobile device 108 to account for privacy anddata protection considerations in example implementations. Inalternative embodiments, these user profiles 168 may also be exchangedand stored on an external server 152 in a database 166 or on a serverbeing included in a SonoBeacon device 102. These user profiles 168 maythen be taken into consideration when providing a user withcontext-related additional content by audio signal synchronization. Thementioned elements of an individual, personalized user profile 168,however, are solely of illustrative and exemplary character and thus inseveral implementations of the present invention, further, additional oralternative elements and characteristics may be stored in such userprofiles 168.

Again coming back to the example of a SonoBeacon user 402 entering amuseum 400 equipped with the SonoBeacon technology, after having paidthe entrance fee he or she may direct him- or herself to the firstexhibition hall 418 of the museum 400. In said first exhibition hall418, another SonoBeacon device 420 may be located. This SonoBeacondevice 420 of the first exhibition hall 418 merely needs to transmit anaudio signal 422 to the user's 402 mobile device 404 so that theSonoBeacon Application displays the relevant explanations correspondingto the exhibits on display in the first exhibition hall 418. Since theSonoBeacon Application has already cached all available explanationsabout all the exhibits in the museum 400 in French, the SonoBeaconApplication does not need to connect to an external database andretrieve the respective information about the exhibits in the firstexhibition hall 418 from there. Instead, the SonoBeacon Application maydirectly display or render the appropriate explanations comprised in itscache. Hence, the SonoBeacon 420 located in the first exhibition hall418 does not need to provide a SonoBeacon Wifi 416 to which mobiledevices 404 with a SonoBeacon Application may connect. Moreover, theSonoBeacon Application does not have to access an external database eachtime the mobile device 404 receives an audio signal 422 from aSonoBeacon device 420. In certain embodiments of the present invention,it may also be feasible to track the location of a user 402 of a mobiledevice 404 by receiving signals from global navigation satellite systemssuch as GPS, Galileo, GLONASS, Beidou etc., thus obliging the need toprovide further SonoBeacon devices 420 for tracing the movement of auser 402 within the museum 400. In these cases, the accuracy of theseglobal navigation satellite systems may be sufficient to inform theSonoBeacon Application on a user's 402 mobile device 404 that a user 402has entered a new exhibition hall such as first exhibition hall 418.Based on this received location information, the SonoBeacon Applicationsubsequently displays or renders the explanations corresponding to theexhibits displayed in this new exhibition hall.

Hence, in such an embodiment, the total number of SonoBeacon devices 420and the number of acoustic signals 422 which have to be transmittedbetween the SonoBeacon devices 420 and the mobile devices 404 can besignificantly reduced and a large amount of energy can be saved.

FIG. 5 illustrates a further example embodiment 500, in which theSonoBeacon technology of the present invention may be employed. A user502 on whose mobile device 504 the SonoBeacon Application is installedenters a SonoBeacon-enabled restaurant 506. For example purposes only,it is now assumed that all relevant sensors of the user's 502 mobiledevice 504 are switched on and that hence it is not necessary to switchon either sensors with the help of other available sensors. However, allembodiments in which such a process of switching on different sensors isnecessary once the user 502 enters the environment of a SonoBeacondevice are obviously included in the present invention.

In a first step, the audio signal transmitter 508 such as e.g. aloudspeaker on the user's 502 mobile device 504 transmits an audiosignal 510 which is received by the audio signal receiver 512 of theSonoBeacon device 514. The signal processing component of the SonoBeacondevice 514 processes the audio signal 510 in such a way that theSonoBeacon software component is finally able to determine that theaudio signal 510 has been received from the mobile device 504 of a user502 who is listed as a regular customer.

The restaurant owner may want to provide a special offer to all regularcustomers, like e.g. 15% off on all of today's lunch specials and hasaccordingly changed the settings in the SonoBeacon software component.Hence, the SonoBeacon software component extracts from the database ordatabases not only a watermark corresponding to today's lunch specials,but additionally a triggering command which should result in a pop-upmessage 516 on a regular customer's mobile device 504 notifying him orher of the 15% discount. Subsequently, the signal processing componentgenerates a combined, encoded and modulated audio signal 518 comprisingboth the watermark and the triggering command. This combined, encodedand modulated audio signal 518 is broadcasted by the audio signaltransmitter 520 of the SonoBeacon device 514 and received by the audiosignal receiver 522 of a regular customer's mobile device 504. Havingperformed the steps of demodulating and decoding and identifying thecorresponding content linked to the watermark and the triggeringcommand, the SonoBeacon Application on a regular customer's mobiledevice 504 displays today's lunch specials 524 and additionally notifiesthe regular customer 502, e.g. by a pop-up message 516 which might beadditionally accompanied by a sound or light effect 526 of the 15%discount granted today to regular customers.

Instead, a ‘normal’ customer 528 who is not listed as a regular customerof the restaurant 506, merely receives today's lunch specials 524 fromthe SonoBeacon device 514. Hence, the audio signal transmitter 520 ofthe SonoBeacon device 514 broadcasts a different encoded and modulatedaudio signal 530 which merely comprises the watermark linked to today'slunch specials 524 to the audio signal receiver 532 of the mobile device534 of such a ‘normal’ customer 528. In another embodiment, it may bepossible to encode a same watermark together with different triggeringcommands, which results in triggering different specific events, while asimilar context-related content is displayed or rendered on differentmobile devices. Alternatively, a same triggering command may be encodedtogether with different watermarks and thus may lead to a similar orsame event to be triggered on the mobile device, while thecontext-sensitive content being displayed or rendered on the mobiledevice may be completely different since it is based on the respectivewatermark encoded in the audio signal. The triggering command thus actsas a second degree of freedom for providing additional context-relatedcontent to users of a SonoBeacon-enabled mobile device, which can berandomly combined with an underlying watermark.

Referring again to the example embodiment 500 of FIG. 5, today's lunchspecials 524 which are displayed on the mobile devices 504 and 534 ofboth regular 502 and ‘normal’ customers 528 may be provided with abutton 536 that a user 502, 528 may select to directly order a specificlunch special. The payment for the ordered lunch special may be effectedautomatically through a user's SonoBeacon account, in which he or shehas provided one or more payment methods, such as credit cards or bankaccounts.

However, in further embodiments of the present invention, a user of amobile device may be provided with further interactive functionalitiesfor listening, voting, gaming or even sending individual contributionsto an owner of a SonoBeacon device. For example, a user of aSonoBeacon-enabled mobile device may be able to vote and comment on acurrent radio broadcast, send a message to the owner of a SonoBeacondevice, take advantage of a gaming option, change or adjust radioprogram preferences, etc. Therefore, in example implementations, a useris provided with interactive options that transform a formerly passiveuser into an active user that directly communicates via the SonoBeaconApplication.

In some embodiments of the present application, the SonoBeacon devicemay additionally take into account further user specific information.For example, the SonoBeacon device may keep a list of previous orders ofa regular customer, based on which he or she may be provided with adifferent menu of today's lunch specials than a second regular customerwho e.g. might have been identified by the SonoBeacon device to be avegetarian.

FIG. 6 illustrates a further example embodiment 600, in which theSonoBeacon technology of the present invention may be employed forproviding access control functionality, thus enhancing security whengranting access to restricted areas. A user 602 on whose mobile device604 the SonoBeacon Application is installed wants to access a restrictedarea such as e.g. a museum or a boarding area at an airport. For examplepurposes only, it is now assumed that all relevant sensors of the user's602 mobile device 604 are switched on and that hence it is not necessaryto switch on either sensors with the help of other available sensors.However, all embodiments in which such a process of switching ondifferent sensors is necessary once the user 602 wants to get access toa restricted area by using the SonoBeacon Application are obviouslyincluded in the present invention.

In a first step, the audio signal transmitter 606 such as e.g. aloudspeaker on the user's 602 mobile device 604 transmits an encoded andmodulated audio signal 608 which is received by the audio signalreceiver 610 of a SonoBeacon device 612. The audio signal 608 comprisesboth a timestamp and identification information unambiguouslyidentifying the user 604 as a user having the right to access arestricted area such as e.g. the restricted boarding area at an airport.In the example illustrated in FIG. 6, the SonoBeacon Application on theuser's 602 mobile device 604 extracts said information about grantingthe user 602 access to the boarding area e.g. from an electronic flightticket 614 stored on the user's 602 mobile device 604 whichunambiguously identifies the user as a passenger of a specific flight.The signal processing component of the SonoBeacon device 612 processesthe audio signal 608 in such a way that the SonoBeacon softwarecomponent is finally able to determine that the audio signal 608 hasbeen received at a specific time from the mobile device 604 of a user602 who is listed as a passenger of a specific flight which is boardedfrom the respective restricted boarding area.

In response to receiving said audio signal 608, the SonoBeacon device612 may trigger an electronic gate 616 to open automatically for alimited timeslot, such as e.g. for 10 seconds starting from the timespecified in the timestamp of the audio signal 608. Obviously, any otherrandom timeslot can be selected by an owner of the SonoBeacon device 612such as e.g. an airline in the present example. Hereby, the SonoBeacondevice 612 can be a separate entity or be physically connected to theelectronic gate 616. Subsequently, user 602, who has been authenticatedas a passenger of a specific flight, is allowed to pass the electronicgate 616 for entering in the restricted boarding area within thespecified timeslot.

Additionally, a signal transmitter 618 of the SonoBeacon device 612 mayalso broadcast an encoded and modulated audio signal 620 to an audiosignal receiver 622 of the user's 602 mobile device 604, notifying auser 602 that he or she has been successfully identified as a passengerof a specific flight and is now allowed to access the restrictedboarding area. Hereby, after performing the steps of demodulating anddecoding and identifying the corresponding content linked to thewatermark and the triggering command included in the encoded andmodulated audio signal 620, a pop-up message 624 may be displayed on thedisplay 626 of the user's 602 mobile device 604, which might beadditionally accompanied by a sound or light effect.

From the forgoing and further it will be appreciated that, althoughspecific embodiments have been described herein for purposes ofillustration, various modifications may be made without deviating fromthe scope of the present disclosure. For example, the methods,techniques, computer-readable medium, and systems for providing dynamiccontext-sensitive customized additional content by broadcasting audiosignals discussed herein are applicable to other architectures and othersystem architectures depicted. Also, the methods, techniques, computerprogram products, and systems discussed herein are applicable todiffering protocols, communication media (optical, wireless, cable,etc.) and devices (such as wireless handset, electronic organizers,personal digital assistants, portable email machines, game machines,pagers, navigating devices such as GPS receivers etc.).

The invention claimed is:
 1. A computer-implemented method fordynamically providing context related additional content to a mobiledevice (108) by broadcasting audio signals by a computing device, themethod comprising: providing the additional content in databases on aserver device, in which each specific piece of content is mapped to aspecific watermark and/or a specific event is mapped to a triggeringcommand; accessing, by the computing device, the server device via awireless network and extracting a specific watermark and/or triggeringcommand from databases; encoding, by the computing device, said specificwatermark and/or triggering command into a digital signal; selecting, bythe computing device, an exactly defined frequency range based oncontinuously scanning noise signals present in the surroundingenvironment of the computing device and modulating, by the computingdevice, the digital signal into an audio signal in the selected exactlydefined frequency range; transmitting, by the computing device, acommand to switch on an audio signal receiver of the mobile device andtransmitting information about the selected frequency range from thecomputing device to the mobile device via the wireless network; inresponse to receiving said command and said information at the mobiledevice over the wireless network, switching on, by the mobile device,the audio signal receiver of the mobile device and tuning the audiosignal receiver to the selected frequency range; broadcasting, by thecomputing device, said audio signal and receiving said audio signal atthe mobile device; demodulating and decoding, at the mobile device, saidaudio signal in order to derive the specific watermark and/or triggeringcommand; searching, by the mobile device, databases via the wirelessnetwork in order to determine the specific content and/or specific eventrelated to the derived specific watermark and/or triggering command;displaying and/or rendering said specific content and/or specific eventon the mobile device.
 2. The computer-implemented method of claim 1,wherein the audio signals may be broadcasted by the computing device inthe ultrasound and/or infrasound frequency range.
 3. Thecomputer-implemented method of claim 1, wherein the audio signalreceiver of the mobile device is already switched on and the informationabout the selected frequency range is transmitted by an acousticbroadband signal from the computing device to the mobile device.
 4. Thecomputer-implemented method of claim 1, wherein any encoded andmodulated audio signals are processed on the mobile device in responseto receiving a triggering signal.
 5. The computer-implemented method ofclaim 1, further comprising providing context-related additional contentfrom the mobile device to the computing device by broadcasting audiosignals from the mobile device to the computing device, wherein theaudio signals comprise a timestamp.
 6. The computer-implemented methodof claim 1, wherein the computing device and the mobile device arefurther equipped with at least one of global navigation satellite systemreceivers and optical sensors.
 7. The computer-implemented method ofclaim 1, further comprising: extracting, by the mobile device, atriggering command from the received audio signal which triggersretrieving all relevant context-related additional content from thedatabases on the server device via the wireless network; caching saidretrieved relevant context-related additional content on the mobiledevices; tracking the location of the mobile device; displaying orrendering context-related additional content on the mobile device basedon the location information of the mobile device.
 8. Thecomputer-implemented method of claim 1, further comprising: encoding, bythe computing device, a same watermark together with differenttriggering commands triggering different specific events occurring whilea similar context-related content is displayed or rendered on the mobiledevice) and/or encoding, by the computing device, a same triggeringcommand together with different watermarks leading to a similar or sameevent to be triggered together with completely different context-relatedcontent being displayed or rendered on the mobile device.
 9. Thecomputer-implemented method of claim 1, wherein encoding, by thecomputing device, said specific watermark and/or triggering command intoa digital signal is performed using error correcting coding and whereina bit length corresponding to the data part of the signal and a bitlength of a shared key change dynamically and wherein additionally aseed for generating the shared key is permuted regularly.
 10. Thecomputer-implemented method of claim 1, wherein the mapping of eachspecific piece of content to a specific watermark and/or of eachspecific event to a triggering command is changed automatically on aregular basis.
 11. The computer-implemented method of claim 1, whereinadditionally user specific parameters are taken into account whenproviding context-related content.
 12. A non-transitorycomputer-readable medium having stored thereon computer-readableinstructions that, when run on a computer, are configured for performingthe method of claim
 1. 13. A computer-implemented method for dynamicallyproviding context-related additional content to a mobile device bybroadcasting audio signals by a computing device in the infrasoundfrequency range, the method comprising: providing the additional contentin a databases on a server device, in which each specific piece ofcontent mapped to a specific watermark and/or a specific event is mappedto a triggering command; accessing, by the computing device, the serverdevice via a wireless network and extracting a specific watermark and/ortriggering command from databases; encoding, by the computing device,said specific watermark and/or triggering command into a digital signal;modulating, by the computing device, the digital signal into an audiosignal in the infrasound frequency range; transmitting, by the computingdevice, a command to switch on a gyrosensor of the mobile device via thewireless network; in response to receiving said command over thewireless network at the mobile device, switching on the gyrosensor ofthe mobile device; broadcasting, by the computing device, saidinfrasound audio signal and receiving said infrasound audio signal atthe gyrosensor of the mobile device; demodulating and decoding, at themobile device, said infrasound audio signal in order to derive thespecific watermark and/or triggering command; searching, by the mobiledevice, databases via the wireless network in order to determine thespecific content and/or specific event related to the derived specificwatermark and/or triggering command; displaying and/or rendering saidspecific content and/or specific event on the mobile device.
 14. Acomputer-implemented system for dynamically providing context-relatedadditional content from a computing device to a mobile device bybroadcasting audio signals by the computing device, the systemcomprising: a server device comprising databases providing thecontext-related additional content, in which a specific piece of contentis mapped to a specific watermark and/or a specific event is mapped to atriggering command; the computing device comprising at least thefollowing components: a software component configured to access thedatabases on the server device and to extract a specific watermarkand/or triggering command; a signal processing component configured toperform the steps of: encoding the specific watermark and/or triggeringcommand into a digital signal and to modulate the digital signal into anaudio signal in a frequency range; and an audio signal transmitterconfigured to broadcast the audio signal; a wireless network connectingthe computing device, the mobile device, and the server deviceconfigured for accessing the database and for transmitting a command toswitch on a receiver or a sensor of the mobile device; the mobile devicecomprising at least the following components: a receiver or sensorconfigured to receive the audio signal broadcasted by the audio signaltransmitter of the computing device; a signal processing componentconfigured to perform the steps of: demodulating and decoding thereceived audio signal in order to derive the specific watermark and/ortriggering command; an application configured to perform the steps of:searching the databases in order to determine the specific contentand/or specific event related to the derived specific watermark and/ortriggering command; displaying and/or rendering said specific contentand/or specific event on a display of the mobile device.
 15. Thecomputer-implemented system as claim 14 recites, wherein: the signalprocessing component of the computing device is configured to select anexactly defined frequency range based on continuously scanning noisesignals present in the surrounding environment of the computing device,wherein the modulating of the digital signal into the audio signalincludes modulating in the selected exactly defined frequency range; thecommand to switch on the receiver or the sensor includes a command toswitch on an audio signal receiver of the mobile device and a command totransmit information about the selected frequency range from thecomputing device to the mobile device; the receiver or sensor of themobile device includes an audio signal receiver configured to receivethe audio signal broadcasted by the audio signal transmitter of thecomputing device; and the signal processing component of the mobiledevice is configured to perform the further step of tuning the audiosignal receiver of the mobile device to the selected frequency range.16. The computer-implemented system as claim 14 recites: the computingdevice broadcasting audio signals in the infrasound frequency range; thesignal processing component of the computing device modulating saiddigital signal into the audio signal in the infrasound frequency range;and the audio signal transmitter configured to broadcast said audiosignal in the infrasound frequency range; the command to switch on thereceiver or the sensor being to switch on a gyrosensor of the mobiledevice; and the receiver or sensor of the mobile device including a gyrosensor configured to receive said infrasound audio signal broadcasted bythe audio signal transmitter of the computing device.